JP3486946B2 - Multicast communication relay device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay device and a transmission / reception device in a computer network system in which a plurality of networks are connected by a relay device.

In a computer network system in recent years, a plurality of networks have been connected by a relay device due to the diversification, complexity and scale expansion of the networks. Also, in various protocols,
Many multicast frames are used to request responses from multiple devices at one time for address confirmation and network management. In such a system, many multicast response frames are returned for one multicast request frame. Therefore, it is required to minimize the load on the network due to the multicast response frame.

[0003]

2. Description of the Related Art FIG. 4 shows a configuration example of a network including a plurality of networks and a relay device that relays them.
FIG. 5 shows an example of a frame format of multicast communication. In the figure, a source station (computer) R that intends to perform multicast communication specifies that the destination address DA in the frame is multicast, displays its own address in the source address SA, and sends a multicast request in the identifier C. Display that there is and send. In response to this, the receiving station A that is the target of the multicast specifies the address of the multicast transmitting station R (the address displayed in the source address SA of the received frame) as the destination address DA, and A frame is displayed in which the own address is displayed in SA and the multicast response is displayed in identifier C. For the originating station (computer) R, there is generally one multicast request frame, but there are multiple multicast response frames returned to it.

In the conventional relay device J, since it is not particularly distinguished that it is a multicast communication, as shown in FIG. 4, the multicast response frame from each station is relayed as it is to the transmitting station R.

[0005]

Therefore, all the response frames are concentrated on the transmitting station R, and the relay device J,
There is a problem that the load of the transmitting station R and the network L2 to which the transmitting station R belongs becomes very heavy. For example, assuming that the number of stations in one network is 100, and a certain station transmits a multicast message to all stations, the response frame to that station is 99. If 10 such networks are connected by a relay device, each network has 100 stations, and the number of response frames to the originating station is 9
Reaching 99. Further, when the networks are connected in multiple stages by the relay device, the number of response frames to the transmitting station is further increased, and the load on the network on the way is also increased.

An object of the present invention is to reduce the load on the network by suppressing the total number of frames by combining and relaying a plurality of response frames for a multicast request frame in a relay device.

[0007]

FIG. 1 is a block diagram showing the principle of the present invention. A plurality of transmission / reception control units 11 to 1n for performing interface control of the networks L1 to Ln capable of multicast communication, and a relay processing unit 2 for relaying the received frame to one or more other networks, and a plurality of networks In a relay device for relaying between L1 to Ln, the first invention is provided with a multicast frame detecting means 3, a frame accumulating means 4, and a frame transmitting means 5.

When the multicast frame detection means 3 receives a frame from the transmission / reception control units 11 to 1n and detects that the frame is a multicast response frame,
The frame is passed to the frame accumulating unit 4, and the other frames are passed to the relay processing unit 2. The relay processing unit 2 determines an appropriate transmission / reception control unit according to the destination address of the passed frame.
Sending to the network via 11-1n is the same as before.

The frame accumulating means 4 accumulates the passed frames, and when a certain condition is satisfied (for example, a certain number of frames is reached, a certain amount of data is reached, a certain time elapses), the frame sending means 5 is activated. To do.

The frame sending means 5 checks the frames accumulated in the frame accumulating means 4, combines those having the same destination address, and passes them to the relay processing section 2 as one frame. In the second invention, the following points are added and changed in the first invention.

The frame accumulating means 4 is provided with a plurality of accumulation areas 41m and a plurality of timers 42m corresponding to the accumulation areas 41m. Multicast frame detection means 3
When receiving a frame from the transmission / reception control units 11 to 1n and detecting that the frame is a multicast request frame, the storage region of the frame storage unit 4 is secured, the source address is registered, and the frame is passed to the relay processing unit 2. .

The frame accumulating means 4 compares the destination address of the passed frame (that is, the multicast response frame) with the registered address, and if they match, stores them in the storage area, and if there is no matching area, relay processing. Part 2
And the accumulated state meets certain conditions (for example,
When there is a storage area in which a fixed number of frames has been reached, a fixed amount of data has been reached, and a fixed time has elapsed by the timer 42m), the frame sending means 5 is activated by designating the storage area.

The frame sending means 5 combines the frames accumulated in the designated accumulation area of the frame accumulating means 4 and delivers them to the relay processing section 2 as one frame. In the third invention, in each of the above-mentioned inventions, instead of the destination address of the frame, the destination address of the frame and the identifier are subjected to coincidence comparison.

In the fourth invention, a source address is further added as a target of the condition comparison of the third invention.

[0015]

In order to simplify the following, a multicast request frame is a request frame, a multicast response frame is a response frame, a station transmitting a multicast request frame is a transmitting station, a station transmitting a multicast response frame is a receiving station, and a destination in the request frame. The contents of the address DA and the source address SA in the response frame are called the receiving station address, and the contents of the destination address DA in the response frame and the source address SA in the request frame are called the originating station address.

Each time the relay device receives a frame, it determines whether or not it is a multicast frame. If it is not a multicast frame, that is, if it is an individual communication frame, a normal relay operation is performed. In the first invention, the request frame also performs the normal relay operation. If it is a response frame, it is stored internally. Then, when a certain condition is achieved (for example, when the accumulating limit is reached or when a certain time elapses), the accumulated response frames are examined and those having the same destination address (source station address) are combined and The relay operation is performed after making one frame. There may be a plurality of destination addresses (source station addresses) of the accumulated response frames, and in that case, the same operation is repeated.

Therefore, the number of frames is reduced because some response frames are sent together to the station that has transmitted the request frame. In the second invention,
When the response frames are stored, they are divided for each destination address (source address), so the combining process is easy and requires only a short time.

In the first and second inventions, when the same transmitting station transmits a plurality of request frames in succession, response frames for different request frames may be mixed and combined. In the invention of 3, the response frames are combined not only in the destination address (source address),
Since the message identifiers are also distinguished, they do not mix and the processing at the receiving station becomes easy. In the fourth aspect of the present invention, the response frames are combined by distinguishing the groups of the receiving station addresses. Therefore, especially when the multicast request designates the group of the receiving stations, they are not mixed surely.

With the above operation, it becomes possible to combine a plurality of response frames to the same destination, the total number of frames is suppressed, and the source station of the multicast request frame,
It is possible to reduce the load on the network to which the transmitting station belongs.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a configuration diagram of an embodiment of the present invention and shows a state in which a plurality of LANs (L1, L2, ... Ln) are connected. The same functions as those in FIG. 1 are designated by the same reference numerals.

In the figure, 11 to 1n are a plurality of transmission / reception control units for transmitting and receiving frames, and are circuits for converting electric signals on the network into data. Reference numeral 3 is a multicast frame detecting means for judging whether the destination of the received frame is a multicast, which is composed of a logic circuit centering on a comparator and compares the destination address and the identifier. Reference numeral 4 denotes a frame accumulating means for combining received response frames, which is composed of a circuit such as a memory buffer divided into a plurality of areas 411 to 41m. Corresponding to them, timers 421 to 42m are provided, which are constituted by timer LSIs or counter logic circuits. A relay processing unit 2 relays the received frame to one or more other networks, and is configured by, for example, a processing device or software. It is essentially the same as the conventional relay processing unit,
Here, the determination of the relay destination, the difference in the frame format of the network, the difference in the procedure, and the like are converted.

The frame format of the multicast communication of the embodiment shown in FIG. 3 will be described below with reference to FIG.
The operation when relaying between networks by the relay device shown in FIG. Here, the networks L1 and L2
.., Ln are stations a1 to b1, b1 to a ...
LAN for connecting n1 to.

Consider a case where the station a1 transmits a multicast request frame to all networks and all stations.
The station a1 designates the multicast address for all stations (M = `FF ') in the M part of the destination address DA of the frame having the format shown in FIG. 3 (1), and requests the identifier C for the multicast (CODE =` 01'). Specify and send.

Stations a2, which belong to the same LAN (L1) as station a1.
When receiving request frames, as in the past, each returns a response frame individually. The relay device of this embodiment receives the request frame through the transmission / reception control unit 11. The received frame is sent to the multicast frame detection means 3 and it is determined whether it is a multicast frame.
In the case of the request frame, the buffer of the frame accumulating means 4 is secured corresponding to the destination address and the identifier inside the request frame, and the received multicast frame is sent to the relay processing unit 2 and the other transmission / reception control units 12 to Each L through 1n
Relay to AN.

Each of the stations b1 to receives the request frame and generates a response frame in response to the request frame. In the response frame, the contents of the source address (source station address) of the previously received request frame are used as the destination address DA, the necessary identifier C is added, and the response frame is transmitted on the LAN.

In the relay device of this embodiment, when the frame received from each transmission / reception control unit is judged by the multicast frame detection unit 3 to be a multicast response frame, it is passed to the frame storage unit. The frame accumulating means 4 checks whether or not the destination address and the identifier of each frame are registered, and if they are registered, they are accumulated in the corresponding buffer of the frame accumulating means 4. If there is no registered buffer, it is passed to the relay processing unit 2. When delivered to the relay processing unit 2, it becomes the same as the conventional individual relay.

The frame accumulating means 4 is provided for each buffer.
When a certain number of frames are accumulated, when the accumulation limit is reached, and when a timeout occurs, the frame sending means 5 is activated. In the frame accumulating means 4, when the first response frame is stored in each buffer (or the buffer may be registered), the timers 421 to 4 corresponding to the respective buffers are provided.
Operate 2m. When this timer expires, it times out.

The frame sending means 5 combines the contents of the buffers of the activated frame accumulating means 4 with each other as shown in FIG.
The combined response frame shown in is generated and passed to the relay processing unit 2. This frame is in the form of one response frame, and the relay processing unit 2 only performs normal relay processing.

Therefore, some response frames are combined and relayed. Due to the time-out, the frames remaining in the buffer of the frame accumulating means are finally combined and transmitted.

When the station a1 receives a frame from the LAN (L1), it recognizes that it is a multicast response frame and a combined response frame, and the DATA part of the frame contains the source addresses of a plurality of response frames. Since the identifier and the data are linked, they may be processed separately.

Although the present embodiment has been described as being configured by hardware (logical circuit) other than the relay processing unit 2, it may be configured by a processor, a memory and software on it other than the transmission / reception control unit. In that case, applying the first invention, the frame accumulating means occupies an area in the memory, accumulates the multicast response frame to the limit of the area, and then the frame transmitting means 5 (also a program) sends the destination. The configuration can be simplified by determining and combining the address and the identifier (the source address may be included in the determination target). If the frame accumulating means has a double buffer structure, the frame receiving process can be performed in parallel during the frame combining process.

Although the network has been described as a LAN, it may be a WAN or LAN and WAN.
May be mixed and the network specifications may be different.

[0033]

As described above, according to the present invention,
Since a plurality of multicast response frames are combined into one in the relay device, the number of response frames from the relay device to the network in which the originating station exists is much smaller than the number of multicast response frames transmitted from the station, In the smallest case, there is only one. Therefore, the load due to the response frame on the source station and the network in which it resides is only slightly higher than when the other network is not connected by a relay device.
As a result, it is possible to reduce the load on the center station that often transmits a multicast frame and the load on the network in which it exists, which contributes to stable operation of the entire network. The effect is more significant when there is a center station that transmits a multicast frame in each of the plurality of networks.

[Brief description of drawings]

[Figure 1] Principle configuration diagram

FIG. 2 is a configuration diagram of an embodiment.

FIG. 3 is a frame format for multicast communication according to an embodiment.

FIG. 4 is an explanatory diagram of the concentration situation of multicast response frames.

FIG. 5: Example of frame format for multicast communication

[Explanation of symbols]

11 to 1n Transmission / reception control unit 2 Relay processing unit 3 Multicast frame detection means 4 Frame storage means 411 to 42m Frame storage area (frame storage buffer) 421 to 42m Timer 5 Frame transmission means L1 to Ln Network (LAN) a1, a2, b1 , b2, ..., n1, n2 Station A Receiver R Originator J Relay device

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Claims (4)

(57) [Claims] 1. A network capable of multicast communication
A plurality of transmission / reception control units that perform interface control
And a relay processing unit for relaying the received frame to the one or more other networks, the relay device for relaying between a plurality of networks, the multicast frame detection hand stage, frame accumulation hand stage
When provided a frame transmission hand stage, the multicast frame detection hand stage, said transmission reception control unit
It receives pressurized et al frame, Ma identifier in the frame
Indicates a response frame to a multicast request frame
When it is detected that is intended, it passes the frame to frame accumulation hand stage, other frame and passes <br/> the relay processing unit, frame accumulation hand stage accumulates the passed frame, certain conditions is satisfied, it starts the frame sending hands stage, frame sending hands stage examines the frames stored in the frame storage hands stage, by combining the same destination address 1
A multicast communication relay device, which is passed as one frame to a relay processing unit . 2. A frame accumulation hand stage is provided with a plurality of storage area, Bei <br/> give a plurality of timer in response to the accumulation area, the multicast frame detection hand stage, transmission and reception controller It receives pressurized et frames, when detecting that the frame is a multicast request frame, transmitting to ensure storage region of the frame accumulation hand stage
Station passes the relay processing unit registers the address, when detecting that the frame is a multicast response frame, passes the frame to the frame accumulation hand stage, the other frames passes the relay processing unit, frame accumulation hand stage, The destination address of the passed frame is compared with the registered source station address and stored in the storage area that satisfies the condition.If there is no storage area that satisfies the condition, it is passed to the relay processing unit and the stored state is constant. If there is a storage region that satisfies the, specify the storage area to start the frame sending hands stage, frame sending hands stage combines the frames stored in the designated storage region of the frame accumulation hand stage 1 The multicast communication relay device according to claim 1, wherein the frame is passed to the relay processing unit as one frame. 3. The multicast communication relay apparatus according to claim 1, wherein the frame identifier is used as a target of the condition comparison in addition to the destination address of the frame. 4. The multicast communication relay apparatus according to claim 1 or 2, wherein the frame identifier and the source address, in addition to the destination address of the frame, are subject to the condition comparison.